[OpenSER-Users] check_from() and calls from a PBX

[Iñaki Baz Castillo]

Hi, I've a PBX (Asterisk) registered in OpenSer as user "pbx at domain".
When Asterisk receives a call from PSTN it calls to OpenSer users with From:
  From: <sip:PSTN_number at domain>

But of course, this can't validate "check_from()" since From username 
(PSTN_number) and auth username (pbx) are differents.

As I solution I don't do "check_from()" if From username is "pbx" but of 
course, it can create security problems.

Other solution is to force "From" username in PBX outgoing calls, but with 
this the callerid number will be "PBX" (that is not very cool for end users 
xD).

Another solution is using "trusted" ips, but this is not valid for me since 
Asterisk is behind a NAT and dynamic IP, and because there can be multiples 
PBX for each domain of OpenSer and I don't want they to have privileges.


Is there any other approach for this?

Thanks for any suggestion.


-- 
Iñaki Baz Castillo
ibc at in.ilimit.es